Your driveway is one of the first things you and your guests will see when pulling up to your house. A properly installed and inviting driveway can add great curb appeal to your home. But the blacktop driveway is not as simplistic as it looks. The base material underneath the blacktop is what gives your driveway the strength and stability it needs to keep it together and functioning properly. Without taking the time to determine and install the proper base material, you will not get the same longevity out of it. Driveway installation can be a costly and time consuming process, so it’s better to get it done right the first time!
The first step in installing a new driveway is to excavate the unsuitable materials from the subgrade (the ground on which the driveway is laid). It should be free of organic material and topsoil, especially clay. The soil beneath the driveway must be of good quality, as to avoid any future issues with cracking, drainage, or movement. The sub-grade must be smooth, firm and even and contoured to match the layout of the driveway. Before installing the base or the blacktop, you will want to make sure excavation is done, the subgrade is suitable, and the soil is compacted. This will ensure the base material and blacktop have a solid foundation to be installed on.
Driveways are built from the ground up so you need to start with a solid base. A good crushed gravel base beneath the blacktop is the secret to a long-lasting driveway. The base is the foundation for a durable driveway, making it critical to pick the right base material. Installing crushed, granular based gravel on a compacted subgrade is the best start to a strong base. The two most important factors when considering base materials are composition and thickness.
Choosing the right base material depends on the particular soil conditions in your area. When selecting a base material you want to use something that will drain well and allows for proper compaction. Crushed coarse gravel has jagged surfaces so they’ll compact and lock together easily, making them perfect for driveway bases. Coarse materials also drain water from under the driveway so ice won’t form and crack the asphalt surface. Base materials vary by region, but two of the best and most commonly used materials are crushed and Con-Bit. Crushed gravel like limestone C-5 and granite C-5 are commonly used as base materials. Another good material to use is Con-Bit, which is recycled concrete and asphalt that is crushed and reused for driveway base material. These materials work well for driveways bases because they drain well and can be properly compacted.
In some areas, a well-drained, sandy soil can act as its own base without needing any or little base materials. In other areas, where clay soils or other poorly compacted soils exist, a brand new base must be laid. Generally, 4-8 inches of base material should be used for your sub-base (closer to 4in for well-draining soils and closer to 8in for poor-draining soils). Local contractors should know about how much base material will be needed for your specific area. The crushed gravel should be installed in layers. The first layer should be 3 to 4 inches thick, graded smooth and then compacted with a heavy rolling machine, before installing the blacktop.
Making sure your driveway is properly prepared before laying the blacktop is the key to a long-lasting and durable driveway. The base materials and preparation involved before putting down the blacktop is a crucial part of the process, and should not be overlooked. Taking the time and effort to correctly install the base is the best way to ensure a durable driveway that will last for many years. Contact New England Enterprises to learn more about driveway base materials and our best practices for driveway installations.